1. Field of the Invention
The present invention relates to an image forming apparatus. More particularly, the present invention relates to an image forming apparatus that allows for easy removal of paper jams, reduces space for disposing a locking means of a cover, and saves production costs relative to the locking means of a cover.
2. Description of the Related Art
Conventional image forming apparatuses include a feeding unit, an exposing unit, a developing unit, a transfer unit, a fixing unit, an out-feed unit, and a cover. Some image forming apparatus, such as a scanner, a copy machine, and a multi-function printer, further include a scanning unit.
The feeding unit feeds a printing medium into an image forming apparatus. The scanning unit optically reads an image of a paper sheet and creates an electrical image signal. The exposing unit forms an electrostatic latent image on the surface of a photoconductor. The developing unit supplies toner as a developing material onto the electrostatic latent image formed on the surface of the photoconductor and develops the electrostatic latent image into a toner image.
The fixing unit, which includes a heat roller and a pressure roller, melts and fuses the toner image onto the printing medium passing through the fixing unit by applying high heat and pressure on the printing medium that has the toner image attached thereon. Because high heat and pressure are applied onto the fixing unit to fuse the toner image onto the printing medium, the printing medium becomes flexible. For this and other reasons, the printing medium often clings to and becomes entangled with the heat roller when the printing medium is fed out through a fixing nip. Therefore, a printing jam, such as an accordion jam, or an accordion effect, may occur.
The out-feed unit includes an out-feed roller and feeds the printing medium out of the image forming apparatus after an image has been fixed on the printing medium.
The cover, which covers a main frame of the image forming apparatus to protect the image forming apparatus from external stress and to beautify the outlook, includes a top cover, a fixing unit cover, and a rear cover.
In a conventional top cover, a rear end portion of the image forming apparatus has been connected with the main frame in a rotating manner, and an upper end portion thereof has been connected with the main frame in an opening and closing manner. However, in an image forming apparatus having a scanning unit, the scanning unit has normally been disposed over the top cover separated by a predetermined distance. The entire top cover has been covered by the scanning unit, and the fixing unit on which a paper jam mainly occurs has been disposed under a rear side of the top cover. Furthermore, to open the upper end portion of the top cover to remove a printing medium caught near the fixing unit, a user has to reach his or her hand downward of the scanning unit. Therefore, it has been very difficult to remove the jammed printing medium.
Additionally, when the paper jam occurs, the rear cover has been opened first and the top cover and the fixing unit cover have sequentially been opened to remove the paper jam. In this case, as in the case of the top cover, the rear cover has been connected with the main frame in an opening and closing manner using a separate member, and the fixing unit cover has been connected with the fixing unit in an opening and closing manner using a separate member.
Accordingly, because a locking means for opening and closing the covers has been provided as a separate member, the number of parts and the number of manufacturing processes have increased, and therefore production costs have increased as a whole.
Accordingly, a need exists for an image forming apparatus having improved covers to facilitate clearing paper jams in the image forming apparatus.